Method and device for the separation of a fluid in a well

ABSTRACT

A method and device for separating a fluid from a formation into several fluid components in a well is disclosed. The method and device include feeding the fluid into a mainly horizontal section of pipe located in a down-hole, mainly horizontal section of the well, such that the fluid is set to flow at a speed through a length of the mainly horizontal section of pipe such that the fluid components are separated and a boundary layer is formed between the fluid components. The fluid components with a lower density are formed in a top part of the mainly horizontal section of pipe and fluid components with a higher density are formed in a bottom part of the mainly horizontal section of pipe. The fluid components with the lower density and the fluid components with the higher density are removed through separate outlets of the mainly horizontal section of pipe.

BACKGROUND OF THE INVENTION

The present invention relates to a method and device for separation of afluid comprising several fluid components, especially separation of awell fluid in connection with a pipe for production ofhydrocarbons/water.

It has previously be proposed that well fluids in vertical wells shouldbe handled using separators. Such separators can comprise semi-permeablefilters which are only pervious to water as described in U.S. Pat. No.4,241,787 or cyclones as described in NO 172426.

A disadvantage with these devices is that they are relativelycomplicated in their construction and/or have many moving parts.Moreover, the aforementioned solutions would require extensivemaintenance/inspection when used in wells having high pressure and hightemperature. Another factor is that these solutions are speciallyadapted for installation in vertical sections of wells. They would alsoresult in extra pressure loss and consume energy.

SUMMARY OF THE INVENTION

The above disadvantages can be avoided with the present invention. Theinvention has been specially developed to be able to separate fluids inhorizontal sections of wells, something which is very advantageous inthe recovery of horizontal formations where the well is formed by meansof horizontal drilling for example.

Other advantages to be achieved when using the invention in connectionwith long (horizontal) wells in particular are:

less pressure loss owing to reduced transport of water together withhydrocarbons

simpler (and smaller) downstream equipment for separation

the amount of water with chemicals released at sea can be greatlyreduced

no salt deposition in production equipment downstream of the well

minimization of hydrates problem

minimization of corrosion problems in transport pipes and processequipment (can lead to use of cheaper materials)

separation of oil/water in the well can lead to simplifications owing tolarge drops, lack of stabilizing surfactants high temperature and lowviscosity

good capacity in relation to energy consumption and investments

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described further by means ofexamples and figures in which:

FIG. 1 shows an oil/water flow pattern diagram;

FIG. 2 shows separation in a well separator as a function of separatorlength, (%) content of water in the product oil;

FIG. 3 shows separation in a well separator as a function of separatorlength, (ppm) content of oil in the product water;

FIG. 4 shows a well with production equipment and a separator;

FIG. 5 shows an embodiment of a separator;

FIG. 6 shows a second embodiment of a separator;

FIG. 7 shows a flow diagram for a separator of the type shown in FIG. 6;

FIGS. 8 a)-c) show a third embodiment of a separator with different flowpatterns; and

FIGS. 9 a)-c) show a fourth embodiment of a separator.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram which shows the flow in a fluid comprising an oilcomponent and a water component in relation to the speed of theindividual component. As the figure shows it has been established bymeans of experiments that it is possible to achieve a stratified flow ifthe speed of flow of the components is of an order of magnitude of lessthan 0.6 metres per second.

FIG. 2 is a diagram which shows the results arrived at in experimentscarried out in a test rig using a light crude oil quality from a fieldin the North Sea. The fluid essentially consisted of the fluidcomponents oil and water. A dispersed flow with a speed of V_(mix) 0.6m/s was initiated in the rig. The tests were carried out to find outwhat criteria have to be satisfied to achieve the desired degree ofseparation.

Other parameters were as follows:

System pressure: 105 bar

System temperature: 70° C.

Oil viscosity: 1.02 mPa*S

Oil density: 736 kg/m³

A separator consisting of a horizontal pipe with an inside diameter ofD=0.78 m was installed in the rig.

The x-axis in the diagram is represented by a parameter as follows:

60.3*(D³/Q)*L

where:

D=inside diameter of the separator pipe (metres)

Q=total volume flow of the well fluid (cubic metres/hour)

L=length of separator pipe

The above parameters include the total retention time for the fluid anda correction factor for varying head (sedimentation distance) at aconstant retention time for the fluid, depending on different values forthe inside diameter of the pipe.

The y-axis of the diagram indicates the percentage quantity of water inthe oil phase.

The diagram in FIG. 3 was produced by means of the experiment describedabove. The y-axis of this diagram indicates the quantity of oil in thewater phase in parts per million (ppm), while the x-axis is the same asin FIG. 2.

It should be noted that the results set out in the diagrams in FIGS. 2and 3 are based on experiments carried out using a specific well fluidand basically only apply to that fluid. Other well fluids would havesimilar separation properties, however, which could therefore bedetermined by means of similar experiments. As well fluids can havedifferent emulsion stability properties, they would require a shorter orlonger retention time in the separator until equivalent separation wasachieved.

Based on the above experiments it is now possible to separate a wellfluid in horizontal wells or wells with horizontal sections ofsufficient length. When a well fluid flows from a reservoir and inthrough perforations in a pipe in a well, the well fluid will assume adispersed flow. Downstream in the production pipe, particularly insections which are essentially horizontal, the fluid components canassume a stratified flow if the speed of flow of the well fluid is lowenough and the retention time is long enough. In the following practicalsolutions will be described for separation of such a flow based on theabove knowledge.

FIG. 4 shows the principal elements in a supplementary solution forrecovery of a formation 2. A pipe is placed in a horizontal section of awell in the formation 2. The pipe 1 comprises a horizontal transportpipe or separation 3 in which there is a separator 6. Upstream of theseparator the pipe 1 is attached to drainage elements or perforations 7which permit well fluid to flow in. Downstream of the separator the pipe1 comprises a vertical riser 4. The pipe 1 can also be attached to awater injection pipe 5 with injection apertures 8 for injection ofseparated water into the formation.

FIG. 5 shows an enlarged/detailed section of a supplementary solution asillustrated in FIG. 4. At its upstream end the horizontal transport pipe3 is attached to an extension pipe 10 with perforations 7 for drainageof the formation 2. Well fluid is fed into the extension pipe 10 andflows in the direction of the separator. The extension pipe can besurrounded by a casing 11 in such a way that an annulus 12 is formedbetween these pipes. The annulus is closed off towards the separator 6by means of a packing 13 and if necessary cement. If necessary theextension pipe 10 can be replaced with any type of supplementarysolution over one or more reservoir sections.

The separator as illustrated in this example is a pipe-shaped body orsection of pipe 14 which has one or more drainage apertures 15 at itsdownstream end to allow water to drain out of the separator 6. Thedrainage apertures are chiefly positioned in the bottom part of thesection of pipe 14. The pipe-shaped body can with advantage besurrounded by the casing 11 so that water which drains out of thesection of pipe 14 through the aperture(s) 15 will be collected in anannulus 16 formed between the section of pipe 14 and the casing 11. Ifnecessary the drainage apertures 15 can be adjustable by means of one ormore movable sleeves 17 which can cover/uncover the apertures. Thesleeves can be positioned inside the pipe 15 or surround it as shown inthe figure. The section of pipe 14 can with advantage be an extension ofa production pipe 22.

The annulus 16 can be closed off with a packing 26 in the downstreamdirection and connected to a water injection pipe 5 for returning waterto the formation 2. If necessary the injection pipe can be connected toequipment such as a valve 30, pumps etc. (not shown) so as to achieve acontrolled return of water to the reservoir. If desirable the waterinjection pipe can be connected via a pipe 34 to equipment 31 such as acyclone for further separation of the water flow. The separated watercan then be fed back to the reservoir via a pipe 32 with injectionapertures 35, while oil containing water is fed back to the productionpipe 22 via pipe 33.

Alternatively the packing 26 can comprise a valve 27 which can be openedand which permits water to be fed to the surface via the annulus 16between the production pipe and the casing. If necessary, just a smallflow of water can be fed up to the surface in this way, or by using aseparate pipe (not shown), for sampling and measuring the oil content ofthe water.

At its downstream end the separator 6 comprises a blocking device 18which closes off the cross-section of the section of pipe 14 with theexception of one or more apertures 19 in the top of the blocking device.The aperture(s) 19 permit(s) oil to flow from the separator to theproduction pipe 22. Upstream of the blocking device there is a gammadensiometer 20 which comprises sensors connected to a signal-processingunit (not shown) which makes it possible to establish the level of theboundary layer (level in vertical direction) between the fluidcomponents. This type of multilevel gamma radiation can be used to bothdetect the level and measure the concentration profile. Moreover, thephase boundary can be established and the oil in the water and water inthe oil determined. This type of registration system representstechnology of which the specialist is master and will therefore not bedescribed in detail here.

Depending on the purity of the water to be separated out from the wellfluid, the boundary layer 25 is regulated high enough in the pipe 14 fora small percentage of water to be fed into the production pipe 22together with the oil if necessary. Regulation of the boundary layer,including achievement of a constant boundary layer at the desired placein the separator, can be carried out by controlling the outflows fromthe separator. This can for example be achieved by means of a valve 28in the production pipe or at the wellhead (not shown) which controls theamount of fluid taken out through the production pipe 22 and regulationof the amount of drained water using the sleeve(s) 17 and/or valve 30 inthe water injection pipe 5. The level of the boundary layer cantherefore be raised or lowered in the section of pipe 14 by means ofreciprocal regulation of the quantity of separated fluids. It should beunderstood that this regulation can be carried out using adata-processing unit (not shown) which processes the signals registeredby the gamma densiometer, processes them in accordance with a setprocedure or software and passes signals to admission devices (notshown) which are connected to the aforementioned valves for regulationof the separated fluids. This represents technology of which thespecialist is master and will therefore neither not be described indetail here.

Another system for regulating the vertical level of the interface 25between the fluid components is to measure the quantity of water in theoil (WIO) and the oil flow (Q oil). These quantities are measureddownstream of the separator and can with advantage take the form ofcontinuous measurements. The measuring equipment can either be locateddown in the well, on a platform or on the surface. Using thisinformation the water in the oil can be plotted as a function of oilflow. As long as the oil/water boundary layer in the separator is lowerthat the oil outlet, the gradient of water in the oil in relation to theoil flow will be low. If the boundary layer approaches the oil outlet,the water in the oil will rise sharply as the oil flow increases. Thisinformation can easily be used to control the oil flow in such a waythat the separator just barely allows water into the oil outlet.

Alternatively the oil in the water (OiW) can be registered and used tocontrol the level of the boundary layer. This registration can be doneat the surface by a small sub-flow of the water which is separated inthe separator being taken up to the surface for analysis/measurement ofthe oil content.

If the speed of the well fluid is too high before it enters theseparator, with the result that the conditions for separation cannot beachieved, the speed can be reduced in several ways. The speed of thewell fluid upstream of the separator can for example be reduced bydecreasing the amount of the fluids extracted at the wellhead andinjection pipe.

Alternatively the speed of the well fluid can be regulated by limitingthe inflow through the drainage elements or perforations. This can forexample be done by closing off the perforations completely or partlyusing one or more movable sleeves 23. Another method can be to installone or more restrictions in the extension pipe 10 or in another suitableplace upstream of the separator. The restriction(s) will help to limitthe speed of the well fluid before it reaches the separator. Suchrestrictions can be bodies which are inserted in the pipe and exhibit areduction in flow area. Disc-shaped restrictions (plugs with a passagefor fluid) can be used for example.

FIG. 6 relates to another embodiment of a separator 106 and shows adetailed cross-section through a separator in a supplementary system asshown in FIG. 4. As in the previous example the horizontal transportpipe 103 is connected at its upstream end to an extension pipe 110 withperforations 107 for draining the formation 102. Well fluid is fed intothe extension pipe 110 and flows in the direction of the separator 106.The extension pipe is surrounded by a casing 111 in such a way that anannulus 112 is formed between these pipes. The annulus is closed offtowards the separator 106 by means of a packing 113 and if necessarycement. In this embodiment the extension pipe is closed off at the inletend of the separator. The extension pipe 110 can if necessary bereplaced with any type of supplementary solution over one or morereservoir sections.

The separator as shown in this example is a pipe-shaped body or sectionof pipe which represents an expansion in relation to the flow area inthe extension pipe 110. The section of pipe can with advantage be thecasing 111. If the diameter of the separator is expanded as shown inthis embodiment, the length of the separator can be reduced.

At the outlet end of the separator there is a production pipe 122 whichis surrounded by the casing 111. The annulus 116 formed between thesepipes is sealed with a packing 118 which has one or more apertures 119in its bottom part to allow water from the separator to flow through.The water can follow the annulus between the production pipe 122 and thecasing 111 either to the surface or to a water injection pipe 105. Oilis fed out of the separator by means of the production pipe 122. Theproduction pipe can project into the inside of the separator withadvantage.

It should be understood that the arrangement described under FIG. 5 forregulation of the boundary layer between the fluid components andregulation of the speed of the well fluid can of course also beimplemented in this solution. The same applies to what was describedregarding the systems for injection and further separation of the watercomponent.

FIG. 7 shows a flow diagram for a separator 106 of the type illustratedin FIG. 6, in which the dispersed oil/water flows into the separatorfrom an extension pipe 110. This example uses a 7″ extension pipe and a10¾″ casing 111 as the outer pipe of the separator. The height of theannulus is specified by the length H (distance between extension pipeand casing).

In this example there is at the distance 8H a coalescence-promotinginsert or screen 140 which is a pierced disk with a cut in its bottompart. When the disc is inserted in the separator the aforementioned cutwill form an aperture 141 which will permit the heaviest fluidcomponents to flow through. The separator can comprise additionalscreens 142, 143 inserted downstream of the first screen. Such insertsor screens can be used to promote separation in such a way that thespeed of the fluid to be separated can be increased in relation to whathas been stated above. As the diagram shows, drops (oil) will coalesceand float up in the top part of the separator. With a speed of 0.9 m/sin the separated flow and a separator length of 26 m the flow will belayered towards the separator outlet (production pipe inlet) in such away that the oil flows into the production pipe 122 and the water entersthe annulus 116. The other parameters for the flow illustrated in thediagram are viscosity 2 cp, oil density 880 kg/m³, rate 4000 Sm³/d,water cut 30%.

FIG. 8a) relates to a third embodiment of a separator 206 and shows adetailed cross-section through a separator in a supplementary system asdescribed in FIG. 4. This embodiment has a number of structuralsimilarities with the preceding examples, but has a diameter which maybe larger than that permitted by the diameter of the casing.

The horizontal transport pipe 203 comprises an extension pipe 210 and acasing 211. Between these two pipes there is an annulus 212 which can ifnecessary be separated from the reservoir using a packing 226. On theupstream side of the separator there is a plug 213 which closes off theextension pipe 210. If necessary a packing 225 can be fitted in theannulus 212 in such a way that it covers the entire area of the annuluswith the exception of one or more apertures 214 in the bottom part ofthe annulus for example. Upstream of the plug 213 the extension pipe hasone or more apertures 215 in its bottom part for example which permitwell fluid being transported in the extension pipe 210 to flow out intothe annulus 212. The fluid passes through the apertures 214 in thepacking 225 and the flows into the separator 206.

The separator as illustrated here is a radial expansion of the outsidedimension of the transport pipe 203, but as in the previous example theoutside dimension can if necessary be the same as the outside dimensionof the casing. The separator comprises an annulus 216 formed between aperforated pipe 218 and a section of pipe 217 which can be an expandedwell hole supported by or closed off by means of an expandable pipe, amaterial hardened in situ or a consolidated formation (not shown indetail). Such pipes can be installed in accordance with inherently knowntechniques. The perforated pipe 218 can be supported at its upstream endby the extension pipe 210. At its downstream end, the perforated pipe isconnected to a production pipe 222. Alternatively the extension pipe,perforated pipe and production pipe can be a continuous pipe with thespecified apertures 215, 221 and plug 213.

The annulus of the separator 216 is equipped to communicate with theannulus 212 at its upstream end and with an annulus 223 formed betweenthe production pipe 222 and the casing 211 at its downstream end.

Well fluid which flows into the annulus 216 will be separated in thatfluid components with the lowest density (oil and possibly gas) willpush up into the top part of the annulus. Here the perforated pipe 218is equipped with outlets or apertures 221 which allow the fluidcomponents to advance into the pipe and flow on downstream of theproduction pipe 222. Fluid components with a higher density such aswater will be collected in the bottom part of the annulus. The annuluscommunicates downstream with annulus 223 and the heavier fluidcomponents will therefore be carried away from the separator in thisannulus.

A packing 219 is fitted in the annulus 223 downstream of the separator.The packing covers the entire area of the annulus with the exception ofone or more apertures 224 in the bottom of the packing. The aperturesallow the heavier, separated fluid components to flow through.

It should be understood that the arrangement described under FIG. 5 forregulation of the boundary layer between the fluid components andregulation of the speed of the well fluid can of course also beimplemented in this solution. The same applies to what was describedregarding the systems for injection and further separation of the watercomponent.

The apertures 221 in the perforated pipe 218 can with advantage bedesigned with the regulation system which is to regulate the level ofthe boundary layer in mind, so that control of the outflows from theseparator are as even as possible. This can be achieved by the aperturesbeing slit-shaped in the vertical direction or triangular with onecorner pointing down (not shown) so that an increase in the level of theboundary layer 227 will produce a limited/progressive increase of waterin the oil which is taken out through the apertures 221.

FIG. 8b) shows the same solution as is shown in FIG. 8a), but withanother flow pattern where apertures 221 are provided on the lower sideor the pipe 218 such that the heaviest fluid components, i.e. the waterflows into the pipe and further up through the production pipe 222,while the lighter components flows up through the annulus 223.

FIG. 8c) shows a further flow pattern, where the pipe 218 is providedwith apertures on the upper as well as the lower side of the pipe, andwhereby the lighter fluid components will flow into the pipe and intothe upper side, while the heavier components will enter into the pipe218 at its lower side. For inside the pipe 218 is provided two separatepipes or channels 228,229 for further separate transport of the tworespective fluid components.

FIGS. 9a)-c) show a fourth embodiment of a separator according to theinvention. Moreover, FIG. 9a) shows a part of a well system 301 withdrainage pipe and branch pipes 302 and a separator 305 with a waterinjection well 304, FIG. 9b) shows in enlarged scale part of the wellshown in FIG. 9a), and FIG. 9c) shows a section along line A—A in FIG.9b).

As is shown in the Figures. the separator includes a transport pipe 303with a joint injection well pipe 304. Oil and/or gas mixed with waterflows via inflow restriction devices 316 from the drainage pipe andbranch pipes 302 to the transport pipe 303 in the separator 305. Herethe water and oil is separated with an upper 308 and lower 307 layerrespectively. Preferably, a threshold 315 may be provided in the areawhere the transport pipe 303 and injection pipe 304 interconnect. Suchthreshold will secure water being present at a certain level.

The water flows further to the water injection pipe 304, while the oilflows upwards to the production pipe 306. The water flowing into thewater injection pipe 304, will contain oil which will be separated inthe upper part of the pipe (oil/water interface at 309). A level control310 (not further shown) detects the oil level and controls a pump 311which injects the water down into the injection pipe 304. The levelcontrol may a capacity type or a combination of capacity andconductivity type control.

It should be emphasized that the drawings are just giving an indicationof the different dimensions and distances being used in connection withany practical solution of the invention. Thus, for instance the distancebetween the transport pipe 303 and the control 310, and the distancebetween the transport pipe and the pump may be of 50 to 100 metres ormore.

The pump 311 as shown in the FIG. 9b) is preferably provided at the endof a completion string 312, close below a packing 313 which separatesthe separator 305 from the lower part of the injection well pipe. Thecompletion string contains (not shown) electric or hydraulic lines forthe supply of energy to the pump.

Besides, the completion string is provided with apertures 314 on theupper side of the packing 313 so that the water being injected to theinjection well may flow through these apertures, further through thestring 312 and to the pump 311.

The invention is not limited to the above examples. Thus, it may also berelevant to use coalescence-promoting chemicals in connection with theseparator. This may be relevant where surfactants are present (e.g.asphalt particles which cannot be held in solution by resins) andprevents drops joining. The effect of the surfactants can becounteracted by oil-soluble emulsion breakers/antifoam agents andasphalt dispersants. If necessary these can be injected continuouslyupstream of the separator.

It is also possible to connect additional valves to the inlet andoutlets of the separator to regulate the inflow of well fluid and theoutflow of the fluid components. The separator can also comprise otheravailable equipment for monitoring/checking that its operatingconditions are being met. It can for example comprise equipment formeasuring the volume flow/speed/pressure/temperature of the fluid/fluidcomponents.

What is claimed is:
 1. A method for separating a fluid from a formationinto several fluid components in a well, said method comprising: feedingthe fluid into one end of a mainly horizontal section of pipe or borelocated in a down-hole, mainly horizontal section of the well; settingthe fluid to flow at a speed through a length of the mainly horizontalsection of pipe or bore such that the fluid components are separated anda boundary layer is formed between the fluid components, whereby fluidcomponents with a lower density are formed in a top part of the mainlyhorizontal section of pipe or bore and fluid components with a higherdensity are formed in a bottom part of the mainly horizontal section ofpipe or bore; and removing the fluid components with the lower densityand the fluid components with the higher density through separateoutlets located at an opposite end of the mainly horizontal section ofpipe or bore.
 2. A method as claimed in claim 1, wherein said settingoperation comprises regulating the speed of the fluid with restrictionsplaced upstream of the mainly horizontal section of pipe or bore.
 3. Amethod as claimed in claim 1, wherein said setting operation comprisesregulating a flow of the fluid components.
 4. A method as claimed inclaim 1, further comprising: detecting a level of the boundary layerwith measuring equipment; and setting the level of the boundary layer byregulating the flow of the fluid components which are removed from themainly horizontal section of pipe or bore during said removingoperation.
 5. A method as claimed in claim 1, further comprising:injecting the fluid components with the higher density back into theformation; and bringing the fluid components with the lower density tothe surface.
 6. A method as claimed in claim 1, further comprising:passing the fluid components with the higher density through a furtherseparation process to thereby separate out fluid components with ahighest density; injecting the fluid components with the highest densityback into the formation; and bringing the fluid components with thelower density to the surface.
 7. A device for separating a fluid from aformation into several fluid components in a well, said devicecomprising: a mainly horizontal section of pipe or bore located in amainly horizontal section of the well having an inlet for said fluid atone end of said pipe or bore and at least two outlets at an opposite endof said pipe or bore, wherein said mainly horizontal section of pipe orbore has a length that allows the fluid to separate into fluidcomponents with a higher density and fluid components with a lowerdensity while the fluid flows through said mainly horizontal section ofpipe or bore such that the fluid components with the higher density formon a bottom part of said mainly horizontal section of pipe or bore andthe fluid components with the lower density form on a top part of saidmainly horizontal section of pipe or bore, thereby forming a boundarylayer in between, wherein said outlets include and outlet for removingthe higher density components and an outlet for removing the lowerdensity components, for said pipe or bore.
 8. A device as claimed inclaim 7, wherein said mainly horizontal section of pipe or borecomprises: an inner perforated pipe; and an outer pipe element, whereinsaid inner perforated pipe and said outer pipe define an annulus.
 9. Adevice as claimed in claim 8, wherein said mainly horizontal section ofpipe or bore has a flow area that is greater than a flow area at saidinlet.
 10. A device as claimed in claim 8, further comprising at leastone insert operable to promote coalescence located within said mainlyhorizontal section of pipe or bore.
 11. A device as claimed in claim 10,wherein said insert is a pierced disk with a cut located in its bottomportion.
 12. A device as claimed in claim 8, further comprisingregulation devices located downstream from said at least two outlets ofsaid mainly horizontal section of pipe or bore, said regulation devicesoperable to regulate the outflow of each the fluid components from saidmainly horizontal section of pipe or bore.
 13. A device as claimed inclaim 12, further comprising: a detecting means for detecting a level ofthe boundary layer; and a signal-processing unit operable to control theregulation devices for the fluid components based on the detected levelof the boundary layer.
 14. A device as claimed in claim 8, wherein saidouter pipe element is an expanded well hole.
 15. A device as claimed inclaim 7, wherein said mainly horizontal section of pipe or bore has aflow area that is greater than a flow area at said inlet.
 16. A deviceas claimed in claim 15, further comprising regulation devices locateddownstream from said at least two outlets of said mainly horizontalsection of pipe or bore, said regulation devices operable to regulatethe outflow of each the fluid components from said mainly horizontalsection of pipe or bore.
 17. A device as claimed in claim 7, furthercomprising at least one insert operable to promote coalescence locatedwithin said mainly horizontal section of pipe or bore.
 18. A device asclaimed in claim 17, wherein said insert is a pierced disk with a cutlocated in its bottom portion.
 19. A device as claimed in claim 17,further comprising: a detecting means for detecting a level of theboundary layer; and a signal-processing unit operable to control theregulation devices for the fluid components based on the detected levelof the boundary layer.
 20. A device as claimed in claim 17, furthercomprising regulation devices located downstream from said at least twooutlets of said mainly horizontal section of pipe or bore, saidregulation devices operable to regulate the outflow of each the fluidcomponents from said mainly horizontal section of pipe or bore.
 21. Adevice as claimed in claim 20, further comprising: a detecting means fordetecting a level of the boundary layer; and a signal-processing unitoperable to control the regulation devices for the fluid componentsbased on the detected level of the boundary layer.
 22. A device asclaimed in claim 7, further comprising regulation devices locateddownstream from said at least two outlets of said mainly horizontalsection of pipe or bore, said regulation devices operable to regulatethe outflow of each of the fluid components from said mainly horizontalsection of pipe or bore.
 23. A device as claimed in claim 22, furthercomprising: a detecting means for detecting a level of the boundarylayer; and a signal-processing unit operable to control the regulationdevices for the fluid components based on the detected level of theboundary layer.